This report describes a family with a visceral neuropathy without extraintestinal manifestations transmitted over at least four generations in an autosomal dominant manner. Four of 7 living patients underwent extensive evaluation including histology, radiography, gastric emptying and secretory studies, esophageal and jejunal manometry, and measurements of plasma levels of gastrointestinal hormones. The only characteristic radiologic abnormality in 7 patients was dilatation of jejunum and ileum. Gastric emptying studies were normal in 2 patients, whereas 2 others showed accelerated emptying of liquids either alone or in combination with grossly delayed solid emptying. Manometry of the esophagus and proximal small intestine and gastric secretory studies were normal. Histologic studies showed hypertrophy of the smooth muscle, a markedly reduced number of argyrophilic neurons, and degenerative changes of argyrophilic neurons and nerve fibers but without Schwann cell proliferation, intranuclear inclusions, or inflammatory cells. This appears to be a familial visceral neuropathy characterized by distinct involvement of the jejunum and ileum as defined radiographically, histology different from that of two previously described forms of familial visceral neuropathy, autosomal dominant transmission, and no evidence for extraintestinal neurologic manifestations.